While i can understand your feelings given your health issues, and i don't relish all the physical changes i'm dealing with myself, i tend to think that like so many other things it varies with individuals. I seem to recall you have home health visits. If so you really should take
@hollydolly's advice and talk with a provider about your state of mind. Or talk with your provider at next office appt. Because nothing speeds up one's decline faster than feeling so unhappy in one's life.
Some things i see as benefits of aging:
Because i no longer have to answer to employer only my energy levels and the weather dictate what i do and when. And i have more time to engage in things that enhance my quality of life.
The older i get the less i've cared what random people think of me, as long as they don't actually interfere with how i live, they can think whatever they like.
For women, it is often a downside that aging makes us almost invisible to many people. But being a person who values solitude, that's kind of a plus for me. Besides i know how to assert myself when necessary.
Do you and your wife talk about this feeling of yours? Does she share similar feelings? If so, she should talk with a professional too.